Can IVF Prevent Genetic Disorders?

IVF combined with preimplantation genetic testing can prevent the birth of children affected by hundreds of known genetic disorders, from cystic fibrosis to sickle cell disease to Huntington’s disease. The process works by creating embryos through standard IVF, testing a few cells from each embryo for a specific genetic condition, and then transferring only unaffected embryos to the uterus. It is not a cure or a gene edit; it is a selection process that identifies which embryos carry a disease-causing mutation and which do not. The technology has matured considerably since its first clinical use in the early 1990s, though it comes with real limitations in accuracy, cost, and emotional toll that are worth understanding before assuming it is a straightforward fix.

How Preimplantation Genetic Testing Works

The umbrella term for this technology is preimplantation genetic testing, or PGT. It comes in several flavors depending on what you are looking for. PGT-M targets monogenic (single-gene) disorders like cystic fibrosis, Huntington’s disease, or sickle cell disease. PGT-SR is designed for people who carry structural chromosome rearrangements, such as translocations, that raise the risk of miscarriage or chromosomally abnormal pregnancies. PGT-A screens for aneuploidy, meaning embryos with the wrong number of chromosomes overall, which is a common cause of IVF failure and miscarriage.

In practice, the process starts like any IVF cycle: ovarian stimulation, egg retrieval, fertilization in the lab. Embryos are then grown for five or six days to the blastocyst stage, at which point a small sample of cells is removed from the trophectoderm, the outer layer that will become the placenta. This day-five biopsy replaced an older approach that took a single cell from a day-three embryo, which had lower accuracy and more potential for harm. One study comparing the two approaches found that a significantly larger proportion of embryos tested as chromosomally normal at the blastocyst stage (about 42%) compared with those biopsied at the earlier cleavage stage (about 24%).{¹} The biopsied cells are sent for genetic analysis, the embryos are frozen, and results come back within days to weeks.

The analytical methods have also changed dramatically. Early PGT relied on a technique called FISH, which could only check a handful of chromosomes at a time. By around 2012, labs shifted to methods that could screen all 23 chromosome pairs, first using microarray technology and then next-generation sequencing.{²} For monogenic conditions, the switch from custom lab protocols to more universal workflows using whole genome amplification and SNP arrays has shortened the waiting time for couples and reduced costs at the laboratory end.{³}

Which Genetic Disorders Can Be Prevented

PGT-M can test for virtually any single-gene disorder where the causative mutation is known. The list runs into the hundreds and includes conditions that follow all the major inheritance patterns.

For autosomal recessive conditions, where both parents must carry a copy of the mutated gene for a child to be affected, PGT-M is routinely used for disorders like cystic fibrosis. One research group demonstrated a universal testing protocol based on next-generation sequencing that can diagnose all known CF mutations at the preimplantation stage.{⁴} Spinal muscular atrophy, Tay-Sachs disease, and beta-thalassemia are other common candidates.

For autosomal dominant conditions like Huntington’s disease, only one parent needs to carry the mutation. Here PGT-M offers something that natural conception cannot: the ability to ensure a child does not inherit the expanded gene without forcing an at-risk parent to learn their own status first. This nondisclosure testing approach has been available since the mid-1990s.{⁵} A Portuguese center reported that out of 90 embryos tested for Huntington’s, 32 were unaffected and suitable for transfer, resulting in two healthy births.{⁶}

X-linked conditions like hemophilia A and Duchenne muscular dystrophy are also well-established targets. In a series of 12 PGT-M cases for hemophilia A, all achieved correct diagnoses, with nine of the twelve mothers receiving embryo transfers and five healthy babies born.{⁷} Similar marker-based approaches have been validated for Duchenne muscular dystrophy carriers as well.{⁸}

PGT-SR addresses a different category: structural rearrangements in a parent’s chromosomes, such as balanced translocations. People who carry these rearrangements are often healthy themselves but face a high risk of producing embryos with missing or extra chunks of chromosomal material, leading to recurrent miscarriage or affected children. Testing embryos for these imbalances before transfer helps avoid those outcomes.{⁹} A large multicenter study of PGT-SR using SNP-based analysis confirmed 100% concordance between the preimplantation results and later prenatal or newborn testing across 415 pregnancies.{¹⁰}

How Carrier Screening Feeds Into the Process

Many couples do not know they carry mutations for recessive diseases until carrier screening reveals it. Expanded carrier screening panels now test for hundreds of conditions at once, and the results increasingly steer reproductive planning. When a fertility center screened over 1,200 couples using an expanded panel, about 1.2% turned out to be carrier couples, meaning both partners carried a mutation for the same disorder. All fifteen of those carrier couples chose to use PGT to transfer unaffected embryos. Strikingly, nearly half of them would have been missed by older ethnicity-based screening guidelines.{¹¹}

This integration of carrier screening and PGT is increasingly viewed as the most effective way to avoid an affected pregnancy while still using the couple’s own eggs and sperm.{¹²} A separate study in a broader population confirmed that the high detection rate of at-risk couples and the high proportion choosing IVF with PGT demonstrated clear clinical utility for expanded carrier screening in the preconception space.{¹³}

Accuracy Is High but Not Perfect

For single-gene disorders, PGT-M is generally very reliable. But “very reliable” and “perfect” are not the same thing, and the gap matters when you are making decisions about which embryos to transfer or discard.

One important source of error is allele dropout, where one copy of a gene fails to amplify during testing, making a carrier embryo look unaffected or vice versa. A systematic assessment across over 500 patients found that allele dropout occurred at roughly 11% of tested loci, distributed across 70 different genes. The rate was lower with newer next-generation sequencing panels (about 4%) than with older Sanger sequencing methods (about 7%), and the difference was statistically significant.{¹⁴} Labs use multiple genetic markers and family linkage analysis to catch dropout events, but it remains a known vulnerability.

For aneuploidy screening (PGT-A), accuracy concerns are more complex. The trophectoderm biopsy samples the outer cell layer, which may not perfectly reflect the genetics of the inner cell mass that becomes the actual baby. This has generated real controversy in the field.{¹⁵} A study re-examining 23 blastocysts flagged as abnormal by PGT-A found that about 21% of non-mosaic aneuploidy calls were false positives, meaning those embryos were actually chromosomally normal. For mosaic calls, the picture was worse: none of the nine mosaic aneuploidies detected by PGT-A were confirmed when the whole embryo was analyzed.{¹⁶}

The practical implication is that some embryos labeled abnormal and discarded may actually have been capable of producing a healthy pregnancy. This is a small study, and false positive rates will vary by lab and method, but it underscores why many clinicians encourage prenatal confirmation testing even after PGT. At one center, about 8% of pregnancies following PGT-M underwent prenatal diagnosis for the monogenic condition, and all results were concordant with the preimplantation finding.{¹⁷}

Success Rates and What Affects Them

Having a genetically tested embryo is one thing; getting pregnant with it is another. A large single-center study of 572 IVF cycles with PGT-M reported a clinical pregnancy rate of about 51% and a live birth rate of about 45% per embryo transfer.{¹⁸} Those numbers are comparable to general IVF success rates with tested embryos, but they mask significant variation. In the same study, patients who also had an underlying fertility problem were roughly 48% less likely to achieve a clinical pregnancy per transfer compared with those using PGT-M purely for genetic reasons.

Maternal age plays a role too. A meta-analysis of PGT-A found that aneuploidy screening increased the live birth rate for women of advanced maternal age but did not improve it for younger women.{¹⁹} This makes biological sense: older women produce a higher proportion of aneuploid eggs, so selecting against chromosome abnormalities has more room to help. A separate meta-analysis found that transferring embryos identified as euploid by comprehensive chromosome screening was associated with higher implantation rates, higher live birth rates, and lower miscarriage rates compared with embryos selected by appearance alone.{²⁰}

A crucial practical point: not every cycle produces a transferable embryo. Some embryos will be affected by the genetic condition. Others may be chromosomally abnormal. Still others may not develop to the blastocyst stage or may yield inconclusive results. Couples sometimes need multiple retrieval cycles before they have an unaffected, chromosomally normal embryo to transfer. This is emotionally and financially draining, and genetic counselors generally prepare patients for the possibility.

What It Costs and Who Has Access

IVF with preimplantation genetic testing is expensive. A cost-effectiveness analysis for spinal muscular atrophy found that the average cost of IVF with combined PGT-M and PGT-A was about $41,000 per attempt. However, the analysis concluded that this was cost-effective compared with unassisted conception for carrier couples, at roughly $22,000 per quality-adjusted life-year gained.{²¹} A similar analysis for BRCA gene mutation carriers reached comparable conclusions, with a cost-effectiveness ratio equivalent to about $44,500 per quality-adjusted life-year.{²²}

Insurance coverage varies enormously by country and even by state within the U.S. Some jurisdictions mandate coverage for IVF but not for PGT; others cover PGT for certain conditions but not others. Many couples pay entirely out of pocket, which limits access to those with means. The regulatory environment varies just as widely. A review of 19 countries found a spectrum from restrictive to permissive frameworks, with differences in which conditions qualify for testing, whether public funding is available, and how oversight is structured.{²³}

The Emotional Side of Testing

The decision to pursue PGT is rarely simple, even for couples with devastating genetic conditions in their families. Research describes the process as highly stressful, with adverse emotional consequences including distress and uncertainty that extend beyond whatever decision the couple ultimately makes.{²⁴} Couples weigh the desire to avoid passing on a disease against the physical burden of IVF, the cost, the possibility of discarding embryos, religious or moral concerns, and the uncertainty of success.

The good news is that once children are born, the psychological outcomes look reassuring. A review of the literature found that studies comparing parents of PGT-born children with IVF and naturally conceived children showed no differences in parental stress.{²⁵} A follow-up of a randomized trial found that preimplantation genetic screening had no effect on parental distress or anxiety, and that distress levels decreased over time regardless of whether screening was used.{²⁶}

What PGT Cannot Do

PGT selects among embryos that a couple naturally produces. It cannot create embryos free of a mutation if every embryo happens to carry it. For autosomal dominant conditions where one parent is affected, roughly half of embryos will carry the mutation. For autosomal recessive conditions where both parents are carriers, about a quarter will be affected. Those probabilities mean that in any given IVF cycle, you might end up with no transferable embryos simply by chance.

PGT also cannot prevent conditions caused by new (de novo) mutations that arise spontaneously during embryo development. It tests for known, inherited mutations. If a genetic disorder appears for the first time in a child without any family history, PGT would not have caught it because no one would have known to test for it.

And the technology says nothing about multifactorial conditions like most cases of heart disease, diabetes, autism, or schizophrenia. These involve complex interactions among many genes and environmental factors. Attempts to extend embryo screening into this territory exist, under the name polygenic embryo screening, but the science is early and the ethics are contentious.

Polygenic Screening and Its Controversies

A few companies now offer polygenic risk scoring for embryos, claiming to estimate a future child’s risk for conditions like type 2 diabetes, heart disease, or certain cancers. Unlike PGT-M, which looks for a single clear mutation, polygenic scoring combines the tiny statistical effects of thousands of genetic variants to generate a risk estimate.

A review in Human Reproduction Update laid out the theoretical case: under best-case scenarios, large relative risk reductions for one or more diseases are statistically possible. But the review also cautioned that practical limitations, particularly the small number of embryos available in a typical IVF cycle and the uncertain future accuracy of the risk models, mean the actual benefit may be considerably smaller.{²⁷} A commentary in Nature Medicine was more pointed, raising concerns about the commodification of embryos, the potential to worsen health disparities, reinforce ableism, and create false hope.{²⁸}

Most professional societies have not endorsed polygenic embryo screening, and healthcare professionals tend to be skeptical about its clinical utility. The polygenic risk scores themselves were largely developed using data from people of European descent, which means they perform poorly in other populations. For now, this remains a speculative extension of what PGT can do, not part of standard care.

Mitochondrial Replacement Therapy

One category of genetic disorder that standard PGT cannot address involves mutations in mitochondrial DNA. Mitochondria have their own small genome, inherited exclusively from the mother, and mutations in it can cause severe neurological, muscular, and metabolic diseases. Because every cell contains thousands of mitochondria, and the ratio of mutant to normal copies varies unpredictably from egg to egg, standard embryo testing cannot reliably predict whether a child will be affected.

Mitochondrial replacement therapy, sometimes called “three-parent IVF,” takes a different approach. The mother’s nuclear DNA is transferred into a donor egg (or embryo) that has healthy mitochondria, producing an embryo that carries the genetic identity of both parents but the mitochondrial DNA of the donor.{²⁹} Several techniques exist, including spindle transfer, pronuclear transfer, and polar body transfer.{³⁰}

The United Kingdom became the first country to legalize mitochondrial replacement in 2015, and a small number of babies have since been born using the technique. It remains illegal or unregulated in most other countries. The approach opens a door that standard PGT-M cannot, but for a narrow subset of families dealing specifically with mitochondrial disease.{³¹}

Newer Sequencing Technology on the Horizon

Current PGT workflows typically require sending biopsied cells to an external genetics lab, with results taking anywhere from a few days to over a week. This delay is one reason embryos are routinely frozen after biopsy and transferred in a subsequent cycle. Emerging technologies, particularly nanopore sequencing, could change that timeline. Nanopore devices are compact enough to operate inside an IVF clinic, and early work suggests they may enable same-day or next-day results for aneuploidy screening.{³²} Whether this translates to meaningful improvements in pregnancy rates or cost remains to be seen, but the direction of travel is toward faster, cheaper, and more clinic-accessible testing. Modern platforms already allow labs to run monogenic and aneuploidy testing simultaneously on the same biopsy sample, which reduces the need for multiple biopsies and streamlines the process for couples who need both types of screening.